COMPARISON OF PREDICTED FAILURE AREA AROUND THE BOREHOLES IN THE STRIKE-SLIP FAULTING STRESS REGIME WITH HOEK-BROWN AND FAIRHURST GENERALIZED CRITERIA

Breakout is a shear failure due to compression that forms around the borehole stress concentration. In this paper, breakout theory model investigated by combining equilibrium elasticity equations of with two Hoek-Brown and Fairhurst generalized fracture criteria, both which are based on Griffith criterion. This provides an explicit equation for width, but depth obtained solving quartic equation. According results in general, situ stresses rock strength characteristics effective developing area, As ratio in-situ increases, area becomes deeper wider. Because zone, envelope criterion lower than criterion, more However, same compressive these width from criteria. Also, theoretical good agreement laboratory Westerly granite.